自动生成验证码图片的工具类,收藏起来备用。

[原]自动生成验证码图片的工具类，收藏起来备用。

用法：直接调用其静态方法即可。

Map<String,BufferedImage> map = ImageUtil.getImage();//获取图片，将图片转换成InputStream流
String key = map.keySet().iterator().next();//获取图片上的字符
BufferedImage image = map.get(key);//获取BufferedImage,赋值给imageStream其中，String为验证码的值，BufferedImage为验证码的图片。

该工具类的代码如下：ImageUtil.java
package action;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
public final class ImageUtil {
private static final String[] chars = { "0", "1", "2", "3", "4", "5", "6",
"7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "东",
"南", "西", "北", "中", "发", "白" };
private static final int SIZE = 5;//验证码长度
private static final int LINES = 20;//干扰线条数
private static final int WIDTH = 200;//图片宽度
private static final int HEIGHT = 100;//图片高度
private static final int FONT_SIZE = 60;//字体高度
public static Map<String,BufferedImage> getImage() {
StringBuffer sb = new StringBuffer();
BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics graphic = image.getGraphics();
graphic.setColor(Color.LIGHT_GRAY);
graphic.fillRect(0, 0, WIDTH, HEIGHT);
Random ran = new Random();
//画随机字符
for(int i=1;i<=SIZE;i++){
int r = ran.nextInt(chars.length);
graphic.setColor(getRandomColor());
graphic.setFont(new Font(null,Font.BOLD+Font.ITALIC,FONT_SIZE));
graphic.drawString(chars[r],(i-1)*WIDTH/SIZE , HEIGHT/2);
sb.append(chars[r]);//将字符保存，存入Session
}
//画干扰线
for(int i=1;i<=LINES;i++){
graphic.setColor(getRandomColor());
graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT), ran.nextInt(WIDTH),ran.nextInt(HEIGHT));
}
Map<String,BufferedImage> map = new HashMap<String,BufferedImage>();
map.put(sb.toString(), image);
return map;
}
public static Color getRandomColor(){
Random ran = new Random();
Color color = new Color(ran.nextInt(256),ran.nextInt(256),ran.nextInt(256));
return color;
}
}
以下是在Struts2中调用该类并将图片转为InputStream的实例：
package action;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import com.opensymphony.xwork2.ActionContext;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class ImageAction {
private InputStream imageStream;
public String execute(){
//获取图片，将图片转换成InputStream流
Map<String,BufferedImage> map = ImageUtil.getImage();
String key = map.keySet().iterator().next();//获取图片上的字符
//将字符写入session
ActionContext.getContext().getSession().put("code", key);
//获取BufferedImage,赋值给imageStream
BufferedImage image = map.get(key);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos);
try {
encoder.encode(image);
imageStream = new ByteArrayInputStream(bos.toByteArray());
} catch (IOException e) {
e.printStackTrace();
}
return "success";
}
public InputStream getImageStream() {
return imageStream;
}
public void setImageStream(InputStream imageStream) {
this.imageStream = imageStream;
}
}。